The following schemes are known in the art for carrying out a daily conversation between a system and a person.
The first one is a task oriented system for having a robot carry out a specific task, as discussed in “Nakano”. A simple system in this category is one that makes a robot produce a predetermined response in response to an oral command. For example, to a user's speech (command) “Tell me today's weather”, a robot responds by orally telling the day's weather forecast. Generally, commands and responses such as this are uniquely defined.
In a sophisticated chat system, a robot carries out a predetermined action after exchanging chat with a user, as discussed in Nakano, identified below. This type of chat systems utilize oral chat technology. A characteristic part of this type of chat system is that the robot carries out a task involving a movement or an action such as to move to call for a designated person.
Another scheme is called a chat system, an example being “Valerie”. A user may enjoy conversation with a robot rather than having the robot to carry out tasks. This system utilizes a known chatbot system. A chatbot (chat robot) may give a user a feeling that the user is talking with a person by having the robot perform gestures in the real space.
The chatbot system is a system for carrying out a daily conversation with a user. As discussed in “Akiyama”, predetermined chat patterns are stored in a database, which is searched responsive to chat input from the user for producing a system response. For example, when a user enters with a keyboard or a microphone “What do you like?”, the system searches response data which meets the word sequence of what-do-you-like-?. A large number of possible user speech entries and system responses thereto are stored in the database. The chat system searches the database and retrieves a response for presenting it to the user through a speaker or a monitor display. The system response may be designed to incorporate a portion of user speech entry into the response.
For example, when a user enters “I was scolded by Dad, yesterday” with a keyboard or a microphone, the chat system may return “What is ‘Dad’ to you?”. This response is produced by inserting a word used by the user into the ‘ . . . ’ part of a response template “What is ‘ . . . ’ to you?”, which has been stored in the database.
In any event, the chatbot system is a system that stores a sort of inquiries and answers into a database for producing system responses to user entries.
Prior Art References
1. [Nakano] M. Nakano, Y. Hasegawa, K. Nakadai, T. Nakamura, J. Takeuchi, T. Torii, H. Tsujino, N. Kanda, H. G. Okuno, “A two-layer model for behavior and dialogue planning in conversational service robots,” in Proc. IROS-2005. 2005.
2. [Valerie] Valerie Web Site: http://www.roboceptionist.com/
3. [Akiyama] Tomotoshi Akiyama, “A program in love ˜ a chatbot made with Ruby” Mainichi Communications, 2005.
In order to make robots, particularly humanoid robots diffuse in the society, robots need to be friendly so that users may use them without having a feeling of congruity. The character and performance of a chat system to be incorporated into the robot are important factors in this respect. The prior art as described above have the following shortcomings.
It is possible to prepare a chat database for a short time usage. However, a large and complicated database would be needed to cope with various situations taking place in daily use of the robot in a long period of time. Such a database can hardly be established beforehand. Further, the scheme of producing a response by extracting a keyword from the user's speech and by inserting the keyword into a predetermined template would hardly develop new chat contents. The chat system short of development possibility is not satisfactory from the standpoint of developing and continuing natural conversation with users.
One way to resolve the above identified problems is to incorporate external information at appropriate timing and present it to the user in conversation. However, mere use of a known information retrieval system that searches information designated by the user and present it to the user is not satisfactory for development and continuing of a natural conversation because, in such a system, the user needs to take a positive action for “requesting or searching information”. This is because the prior art system is a passive system. With such a prior art system, the user will be bored and feel a stress, and will not use the system in a daily life for a long period of time.
Accordingly, it is an object of the present invention to provide a chat information system capable of developing and continuing a natural conversation with a user.